Measurements ofgfactors and lifetimes of low-lying states in62–70Znand their shell model implication

Abstract

The g factors of the first ${2}^{+}$ states and the $B(E2)$ values of the ${(2}_{1}^{+}\ensuremath{\rightarrow}{0}_{1}^{+})$ transitions have been determined with high precision for all stable doubly even Zn isotopes employing the combined technique of projectile Coulomb excitation in inverse kinematics and transient magnetic fields. In addition, this systematic study was supplemented by a first measurement of radioactive ${}^{62}\mathrm{Zn}$ ${(T}_{1/2}=9.2 h)$ formed in an $\ensuremath{\alpha}$-transfer reaction with a ${}^{58}\mathrm{Ni}$ beam. The ${g(2}_{1}^{+})$ values obtained are in good agreement with previous data but provide considerably higher accuracy. The same quality of agreement was found for the $B(E2)$ values with the exception of ${}^{70}\mathrm{Zn}$ where the measured value is slightly smaller. The experimental data were compared with large scale shell model calculations considering configurations in the $\mathrm{fp}$ and $\mathrm{fpg}$ model spaces with inert cores of ${}^{40}\mathrm{Ca}$ and ${}^{56}\mathrm{Ni},$ respectively.